Provided are an image processing system and an image processing method. An image processing method includes: constructing a plurality of grids on an image; extracting features of the image; estimating a grid motion vector of each of the plurality of grids, based on a first motion vector of each of the features; estimating a second motion vector of each feature based on the grid motion vector; and detecting a moving object based on a difference between the first motion vector and the second motion vector.